Anderson



E'. F. w. ALEXANDERSON.

WIRELESS TELEPHONE SYSTEM.

APPLICATION EILED AUG.24. 1916.

1 3 1 3,04 1 Patented Aug. 12, 1919.

InVenLcT:

Has fittern e g UNITED STATES PATENT OFFICE.

' ERNST ILW. ALEXANDEBSON, SCHIENECTADY, NEW YORK, ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW'YORK.

WIRELESS-TELEPHONE SYSTEM.

Specification of Letters Patent.

PatentedAug. 12, 1919.

Application filed August 24, 1916. Serial No. 116,634.

To all whom it may concern.

Be it known that I, ERNST F. \W. ALEX- ANDERSON, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Wireless-Telephone Systems, of which the following is the specification.'

My present invention relates to wireless telephone systems, and more particularly to systems in which a two way conversation may be maintained by wireless means between two widely separated points. In carrying on a telephone communication b transmitting position as soon-as the speaker starts to talk into the telephonetransmitter. The great disadvantage of such systems, however, has been that the one listen ing is unable to interrupt the one talking. It has also been proposed to connect both the receiving and transmitting apparatus permanently to the antenna and by means of balanced circuits eliminate the effect of the transmitting apparatus upon the receiving apparatus. Practical difficulties however, have arisen in the operation of such a system and as far as the present applicant is aware no success has ever been obtained with this arrangement.

The object of the present-"invention is to overcome the disadvantages present with systems of the types referred to and to pro- .vide a system in which a continuous twoway conversatlon may be carried on as readily as in the case of an ordinary wire connection. A further object of the invention is toprovide a system whereby any subscriber connected with a central telephone exchange may be put into communication by wireless with any subscriber connected to a telephone exxchange at a distant point.

In carrying my invention into effect I provide at each end of the transmission system two antennae, one for transmitting signals and the other for receiving, the two antennae being located at a great enough distance from each other so that the effect of the transmitted signals may be eliminated in the receiving apparatus. In addition I provide connections whereby a telephone subscriber connected to a central exchange mayi be connected simultaneously with both the receiving and transmitting antennae.

My invention will best be understood by reference to the following description taken in connection with the accompanying drawing in which I have illustrated dlagrammatically one way in which my invention may be carried into eflect. I have indicated in the drawing connections for two complete stations 1 and 2, which may be located at any distance from each other desired. At station 1 there is a transmitting antenna 3 and receiving antenna 4,'and at station 2 a transmitting antenna 5 and a receiving antenna 6. These antennae are all provided with the usual tuning indiictances.

7. At station 1 I have indicated a subscribers circuit 8 connected to a central exchange 9 and connections may be made through this central exchange by means of line 10 to the transmitting antenna and through line 11 to the receiving antenna. The transmitting antenna has connected thereto a source 12 of high frequency alternatingcurrent and the telephone currents passing over line 10 may be utilized to control the output of the source of high frequency current by means of a magnetic device 13 which may be of the type described in my U. S. Patent No. 1,206,643. At the receiving antenna 4 there may be connected any deslred form of detector and I have indicated diagrammatically a crystal, de-

tector 14. The signals, which are received may be .transmitted from the'detecting apparatus through the transformer 15, over the line 11 and through the central exchange to the subscribers instrument 16, or they may be amplified in any convenient way before they are transferred to line 11, as for example, by means of a relay such as that describedin Patent No. 1,038,910 to Von Lichen & Reiz. The arrangement used at station 2 may be an exact duplicate of the one illustrated at station 1 although in the present case I have indicated a line 17 connecting the antenna; 5 and 6 and a branch line 18 extending from this line to the central exchange.

In the operatlon of this. system it will be.

apart the effect of the transmitted signals upon the receiving apparatus at the same station may be eliminated to such an extent as not to interfere with conversation. The distance by which the two antennae of the station must be separated will of course depend upon the stren th of the signals transmitted and the di erence in the two frequencies which may be employed.

While I have indicated diagrammatlcally a certain form of receiving and transmitting apparatus, connections whereby the subscriber may be connected to the wireless system; it will be apparent that many modifications in the particular form of apparatus used and m the specific manner in which the connections are carried out may be made without departing from the scope of my invention as set forth in the appended claims.

by Letters Patent of the United States, is

1. The combination in a wireless signaling system of an antenna for transmitting signals, a source of high'frequency energy and apparatus for controlling the same connected to said antenna, a receiving antenna having suitable receiving apparatus operatively connected thereto at all times and located at such a distance from the transmitting antenna that the efiect of the transmitted signals may be eliminated in the receiving apparatus, a telephone line and means for connecting the telephone lme simultaneously to both the transmitting andv receiving apparatus.

g 2. Means for carrying on a two-way telephonic conversation between two widely separated points comprising an antenna for transmitting signals, a source of high frequency energy and apparatus for controlling the same connected to said antenna, a re ceiving antenna having suitable receiving apparatus operatively connected thereto at all times and located at such a distance from the transmitting antenna that the effec'at of the transmitted signals may be e,lim1l"qatcd in the receiving apparatus, a telephone line, means for connecting the telephone line simultaneously to both the transmitting and receiving apparatus, a second telephone line, and means for connectingthe second telein a manner as well as certain specific.

v a with the second mentioned What I claim as new and desire to secure trolling the same connect two separate antennae arranged similar to the firstmentioned antenna.

3. In a wireless telephonesystem, a subscribers circuit, a central exchange, a transmitting antenna, a receiving antenna located at such a distance from the transmitting antenna that the effect of transmitted signals may be eliminated in receiving apparatus operatively connected thereto at all times and means for connecting the subscribers circuit through the central exchange phone line to simultaneously with' both the transmitting and receiving antennae. v

4. in a wireless telephone system, a subscribers circuit, a central exchange, a transmitting antenna, a receiving antenna located at such a distance from the transmitting antenna that the effect of transmitted sig-' nals may be eliminated from the receiving apparatus operatively connected thereto,

. means for connecting the subscribers circuit throu h the centralexchange simultaneously .with t e transmitting and receiving antennae,

a second subscribers circuit located at a distance from the first subscribers circuit, a second central exchange to which the second subscribers circuit is connected, transmit- 'ting' and receiving antennae arranged in a manner similar to the first mentioned antennae, "and means for operatively connecting the second subseribers circuit simultaneously receiving antennae.

5. Means for carrylng on a two-way 'WII'Q' signals, a source of high frequency energy of definite frequency and eapparatus for conto said antenna,

transmitting and less telephonic conversationbetween two. widely separated stations comprising an L antenna at the first station for transmitting a receiving antenna having suitable receiv- I ing apparatus operatively connected thereto at all times, located at such a distance from the transmitin antenna and so arranged that the receivlng apparatus will be unaf- I fected by the signals, transmitted, a telephone circult, means for connecting the telephone circuit to both the transmitting and receiving apparatus, a second telephone'line,

separate transmitting and receiving antennae at the second station, means for connecting the second telephone line to said antennaeat the second station, the receiving antenna being tuned to the frequency of'the high frequency source at the first station and a second source of high frequency energy of a different frequency from the first source connected. to the second mentioned transmitting antenna, the receiving antenna at the first station being tunedto the frequency of the second mentioned source of high frequency energy.

6. The combination n a'wireless signaling system of an antenna for transmitting signals, a source of high frequency energ of a definite frequency and an apparatus Will be unaffected by the signals transmitted, for controlling the same connected to said a telephone line and means for connecting 10 antenna, a receiving antenna tuned to a'frethe telephone line simultaneously to both the quency 'difi'erent-from that of said source transmitting and receiving apparatus.

having suitable-receiving apparatus opera- In witness whereof, I have hereunto set tively connected thereto at all times and 10- my hand this 23rd. day of August, 1916.

cated at such a distance from the transmitv a 4. ting antenna that the receiving apparatus ERNST F. W. ALE'XANDERSON. 

